I've been unsuccessful in finding proper information online about how to REALLY keep brushes clean when using them to apply rubber latex for making molds.
All the sources mention using dish soap, but all of them are absolutely unspecific about it.
So years ago, when I first started using rubber latex, I wasted a few brushes.
I hate wasting!
This past week, I've been working with latex again, both as final product and as molds (different projects).
So I decided to solve this once and for all, after another intensive search turned no specifc methodical solution.
Today, by simple logic and remebering what went wrong before, I found a method that works, and here it is!
UPDATED August 2nd, 2010
1. choose a good quality long haired brush (I use a flat hogs bristle brush). The lenght gives it suppleness and bounce, allowing for softer and more precise application of latex.
2. Find a small narrow short jar, and fill it with liquid dish soap. It must be enough to cover all the jair on the brush, and part of the ferule (metal part).
3. dip brush into dish soap, gently press with your fingers to make sure the dish soap gets deep into the brush.
Leave brush in it for a few minutes (I prepare my model for molding during this time)
This is an added precaution to ensure that the soap really is permeating every hair on the brush.
4. pour your rubber latex into a small container, such as a small pudding cup or a glass. Plastic is best, it can be cut to size, and cleans up easily: just peel off latex when dry.
The small container makes it easier to handle the latex (compared to using the big jug or gallon container), and helps prevent dipping the brush too deep.
5. remove excess dish soap by rubbing against the mouth of the jar, therefore recuperating it.
6. Dip ONLY the end of the brush into the latex. This is important because the ferule'Ms exit for the hair is where latex and paint like to accumulate, and make the hair go wild and useless for precision work. Nearly impossible to clean once it is set there.
Brush the latex gently onto your model, either by sliding or by stippling, using the tip of the brush, without applying much pressure. This is imprtant to keep proper detailing on the first three coats at least. DO NOT squeeze the excess latex back into your latex cup. You would contaminate your latex with dish soap, which could, in theory, cause structural problems on your project.
7. If your surface is large or complex and takes a while to cover, take a break after ten or 15 minutes, to wash your bush, even if you are not finished, and when the brush is clean, just redip in dish soap, and start working again.
8. CLEANING the brush: start with a squirt of dish soap in your hand (gloved if you are allergic to latex), mix the soap into the brush (tip only again), and then wash gently with COLD tap water. to water makes latex set instantly! DO NOT srub the brush into your hand. DO NOT reverse the brush to force water near the ferule. Those are very bad abuse on any brush, but alas quite common "techniques" in the artistic and construction fields. Better to gently brush your hands directionally, as if you were painting it. Repeat rinsing and soaping until you are sure thebrush is clean. Suspend upside down to dry.
Occasionally, after a work session, it is good to treat your brush to a little bit of hair conditionner. It helps keep them alive longer. Just don't, forget to rinse toroughly, or else the conditonner would affect your next painting or moldmaking job.
Found out after three days of using this method: there may be just enough residual dish soap within the depth of the brush to be enough to wash it without needing to add any more.
9. No matter what precautions you take, you will eventually get some small beads of latex forming at the end of your brush. Use more dish soap and rub it well. Then pinch those beads out of the brush.
Here's to the health of your brushes, and more precision in your work!